Amitriptyline: an antidepressant prescribed for nerve pain and migraines
What is amitriptyline?
Amitriptyline is an antidepressant medicine that's also used in lower doses to treat nerve pain and prevent migraines. It has a sedative effect that can also help anxiety and sleeping problems associated with these conditions.
Amitriptyline is only available on prescription. It comes as tablets (10mg, 25mg and 50mg strengths) and liquid.
What is amitriptyline used for?
Amitriptyline is used for:
▪️ Treating nerve pain (neuralgia) caused by nerve damage, for example due to diabetes, stroke, injuries, chemotherapy, amputation (phantom limb limb) or shingles (postherpetic neuralgia).
▪️ Preventing migraines and chronic tension headaches.
▪️ Treating depression when other antidepressants haven't worked.
▪️ Amitriptyline is also licensed to treat bedwetting (nocturnal enuresis) in children aged six years and over, however, it's only used for this when other non-drug and drug treatments have not been effective.
Key info to know about amitriptyline
▪️ Amitriptyline is not addictive. It won't change your personality or make you feel euphorically happy.
▪️ You need to take amitriptyline regularly every day for it to be effective.
▪️ It doesn't work straight away. You may feel some benefit in the first couple of weeks, but it usually takes four to six weeks before you feel the full benefit. Most people need to keep taking it for several months.
▪️ Common side effects include feeling sleepy or dizzy, so it’s best to take your daily dose in the evening. Avoid driving if affected.
▪️ Other common side effects include dry mouth, constipation, difficulty passing urine and headaches.
▪️ You should avoid drinking alcohol while taking amitriptyline because it will make you more likely to feel sleepy, dizzy or confused, or to have blurred vision. This effect is likely to be worse if you drink alcohol when you start treatment or after any dose increases.
▪️ Amitriptyline may cause drowsiness, reduced alertness, dizziness and blurred vision and so may reduce your ability to drive or operate machinery safely. Do not drive or operate machinery until you know how this medicine affects you and you are sure it won't affect your performance.
▪️ Don’t suddenly stop taking amitriptyline because this can cause side effects - when you stop treatment this needs to be done slowly.
How does amitriptyline work?
Amitriptyline is a type of medicine called a tricyclic antidepressant. It acts on nerve cells in the brain and spinal cord.
For depression
Amitriptyline works in depression by enhancing the activity of neurotransmitters called serotonin and noradrenaline in the brain. Neurotransmitters are natural body chemicals that act as chemical messengers between the nerve cells. Serotonin and noradrenaline are known to be involved in regulating emotions, mood and behaviour, among other things.
In depressive illness less serotonin and noradrenaline than normal is released from nerve cells in the brain. Amitriptyline prolongs the effects of serotonin and noradrenaline that have been released in the brain. Over time this helps to lighten mood and relieve depression.
For nerve pain, migraine and tension headache
It's not fully understood how amitriptyline works in these conditions, but it is not related to it's antidepressant action. It seems to relieve pain by interfering with the way pain signals are transmitted in the brain and spinal cord.
How long does it take to work?
Some people find they start to feel better in the first couple of weeks, and if you've been having problems sleeping you should find that amitriptyline helps with this straight way. However, it usually takes at least four to six weeks before you feel the full benefit of taking amitriptyline for pain, migraine or depression, so it's important to persevere with taking it, even if it doesn't seem to make much difference at first. Most people will then need to keep taking amitriptyline for several months.
If you're taking amitriptyline for depression and you feel your mood has got worse, or if you have any distressing thoughts, or feelings about suicide or harming yourself in the first few weeks, or indeed at any point during treatment or after stopping treatment, then it's very important to talk to your doctor.
Who can and cannot take amitriptyline?
Most adults can take amitriptyline. Specialists may also prescribe it off-licence to treat nerve pain in children aged 2 to 17 years.
Amitriptyline is not suitable for:
People with severe liver disease.
People who've recently had a heart attack.
People with an irregular heartbeat (arrhythmia) or heart block.
People in a manic phase of bipolar disorder (manic depression).
People who have taken a type of antidepressant called a monoamine oxidase inhibitor (MAOI) in the last two weeks.
People with rare hereditary blood disorders called porphyrias.
Some people, including the elderly, may need a lower amitriptyline dose or extra monitoring. Make sure your doctor knows if you:
have liver problems
have heart disease (amitriptyline can sometimes cause heart problems)
have an overactive thyroid gland
are taking thyroid medication for an underactive thyroid gland
have a tumour of the adrenal gland (phaeochromocytoma)
have difficulty passing urine, for example because you have an enlarged prostate gland (amitriptyline can make this worse)
have been constipated for a long time (amitriptyline can make this worse)
have a history of raised pressure in the eye or glaucoma
have diabetes (amitriptyline may cause changes in blood sugar levels so your doctor may ask you to check your blood sugar more frequently)
have epilepsy, brain damage, or are going through drug or alcohol withdrawal (amitriptyline may increase the risk of having a seizure)
suffer from a psychotic illness such as schizophrenia
suffer from bipolar affective disorder (manic depression)
are receiving electroconvulsive therapy (ECT).
Is amitriptyline safe to take if pregnant?
Amitriptyline is not usually recommended for treating pain in women who are pregnant because there are safer painkillers available.
If you're taking amitriptyline for depression and you get pregnant it may be possible to keep taking it, providing you have talked to your doctor about the risks and benefits of taking amitriptyline compared with stopping treatment or using other treatments.
This is particularly important in the first and third trimesters, where amitriptyline could potentially have harmful effects on the baby. Symptoms that resemble side effects or withdrawal symptoms of amitriptyline have been seen in new-born babies whose mothers took amitriptyline in the third trimester.
If you get pregnant and decide to stop taking amitriptyline you doctor will advise you how to do this. Do not stop taking amitriptyline suddenly, as this can cause withdrawal symptoms such as nausea, vomiting, loss of appetite, headache, giddiness, chills, insomnia, restlessness or anxiety. Your doctor will give you instructions on how to stop treatment gradually to avoid these effects.
Read more about using amitriptyline during pregnancy here
Is it safe to breastfeed while taking amitriptyline?
Get advice from your doctor if you want to breastfeed while taking amitriptyline. Amitriptyline passes into breast milk, but only in very small amounts that are unlikely to be harmful to a nursing infant. If you're taking amitriptyline for depression it's usually fine for you to breastfeed providing your baby is healthy, wasn't born prematurely, and is monitored for potential problems such as drowsiness. However, do always check with your doctor first, because various factors need to be taken into account.
Amitriptyline: dosage instructions
▪️ You can take amitriptyline tablets and liquid either with or without food.
▪️ The amitriptyline dose prescribed depends on what you're taking it for, your age and any other conditions that you have. Try to always take your medicine at the same time each day - this will help you to remember it.
▪️ For nerve pain, migraine and tension headache: A typical starting dose for an otherwise healthy adult is 10mg, taken once a day in the evening. Your doctor may increase your dose gradually as you get used to the medicine.
▪️ For depression: A typical starting dose for an otherwise healthy adult is 25mg twice a day. Your doctor may increase your dose gradually as you get used to the medicine.
▪️ Missed dose: If you forget to take a dose of amitriptyline take it as soon as you remember, unless it's nearly time for your next dose. In this case leave out the forgotten dose and just take your next dose as usual. Do not take a double dose to make up for a missed dose.
How long should I take amitriptyline for?
Keep taking amitriptyline regularly until your doctor tells you to stop.
For nerve pain, migraine and tension headache: You need to keep taking amitriptyline for at least six weeks to see if it helps you. If your pain improves, or you are getting fewer migraines or headaches, then you can keep taking amitriptyline for as long as it still helps you. So for example, your doctor might ask you to gradually lower your dose from time to time to see if the problem comes back - and if it does it's fine to continue taking amitriptyline. Some people take it for months and sometimes years.
For depression the current recommendations are that antidepressants are continued for at least six months after recovery (two years if you suffer recurrent depression). This has been shown to help prevent the depression coming back after the medicine is stopped.
Do not suddenly stop taking amitriptyline unless your doctor tells you, because this can cause side effects like feeling sick, dizzy, shivery, restless or anxious, loss of appetite, headache and difficulty sleeping. These symptoms are temporary and are not due to addiction or dependence on the medicine. They can usually be avoided by stopping the amitriptyline gradually, usually over a period of weeks or months, depending on your individual situation. Follow the instructions given by your doctor when it is time to stop treatment.
What are the side effects of amitriptyline?
Medicines and possible side-effects can affect individual people in different ways. The following are some of the side-effects which may be associated with this medicine. Just because a side-effect is listed here, this does not mean that everyone who uses this medicine will experience it, or any side-effect. If you are concerned about side-effects or experience an adverse reaction from your medicine, consult your doctor.
Common side effects of amitriptyline
Dry or sore mouth. A dry mouth may increase the risk of tooth decay so it’s important to practice good oral hygiene and visit your dentist regularly for check-ups if you’re taking amitriptyline for long periods of time.
Feeling sleepy, weak or tired. Don’t drive if affected.
Blurred vision.
Constipation.
Difficulty passing urine.
Feeling sick.
Stomach ache.
Headache.
Drop in blood pressure that makes you feel dizzy or lightheaded when getting up from lying down or sitting. This is more of a problem when you first start taking the medicine, or if you’re taking a diuretic medicine such as furosemide. To avoid this try getting up slowly. If you do feel dizzy, sit or lie down until the symptoms pass.
Other possible side effects of amtriptyline
Involuntary muscle movements such as tremors or twitching.
Skin reactions such as rashes, itching or increased sensitivity to sunlight.
Sweating.
Feeling anxious, agitated, restless or confused.
Sexual problems such as reduced sex drive or erectile dysfunction.
Enlargement of the breasts and production of breast milk.
Changes in behaviour.
Changes in appetite and weight.
Changes in the way things taste.
Seizures (rare).
Fast, irregular or weak heartbeat (rare). Tell your doctor if you notice a change in your heartbeat.
Disturbances in the normal numbers of blood cells in the blood (rare). Tell your doctor know if you get any unusual bruising or bleeding, signs of infections such as a fever or sore throat.
Drop in the amount of sodium in the blood (rare), particularly in elderly people. Tell your doctor if you develop drowsiness, confusion, muscle twitching or convulsions, so your blood sodium level can be checked if necessary.
You should read the patient information leaflet that is supplied with your medication for more information about side effects associated with amitriptyline. You can find a copy of this here
Can I take other medicines with amitriptyline?
While you're taking amitriptyline you should always check with your doctor or pharmacist before taking any non-prescription medicines, to make sure that the combination is safe.
Painkillers with amitriptyline
If you need to take a painkiller it's safe to take paracetamol, aspirin or ibuprofen with amitriptyline. However, it's best to avoid taking co-codamol, codeine or other opioid painkillers because these could worsen any drowsiness or constipation that you may be experiencing.
Cold and flu remedies with amitriptyline
You shouldn't take cold and flu remedies that contain a decongestant such as pseudoephedrine or phenylephrine while you're taking amitriptyline.
Antihistamines with amitriptyline
Antihistamines such as cetirizine or loratadine are safe to use with amitriptyline, as they don't cause drowsiness. Avoid those that can cause drowsiness like chlorphenamine or promethazine, because these will make you more sleepy. They can also increase the risk of getting side effects like a dry mouth, constipation, difficulty passing urine and blurred vision.
Herbal remedies with amitriptyline
Avoid taking the herbal remedy St John's wort (Hypericum perforatum), as it can increase the risk of getting side effects from amitriptyline.
Medicines that cause drowsiness with amitriptyline
You're more likely to feel sleepy if you take amitriptyline with other medicines that can cause drowsiness, such as:
antihistamines that can cause drowsiness, such as chlorphenamine, promethazine
baclofen (severe muscle weakness may also occur with this combination)
benzodiazepines, such as diazepam, temazepam
sleeping tablets, such as zopiclone
strong opioid painkillers, such as morphine, codeine, co-codamol, tramadol.
Medicines that lower blood pressure with amitriptyline
You may be more likely to feel dizzy or faint if you take amitriptyline alongside medicines that lower blood pressure, including medicines used to treat high blood pressure and medicines that can lower blood pressure as a side effect, for example benzodiazepines. If you're taking medicines that lower blood pressure, tell your doctor if you feel dizzy or faint after starting treatment with amitriptyline, as your doses may need adjusting.
Other medicine interactions with amitriptyline
You are more likely to get a dry mouth, constipation, difficulty passing urine or blurred vision if you take amitriptyline with other medicines that can cause these kinds of side effects, such as:
anticholinergics for urinary incontinence, for example tolterodine, oxybutynin
anticholinergics for Parkinson's symptoms, for example procyclidine, trihexyphenidyl
antispasmodics, for example hyoscine, atropine
some antipsychotics, for example chlorpromazine, clozapine
certain other antidepressants
some antisickness medicines, for example meclozine, cyclizine.
If you take other medicines or drugs that enhance serotonin activity in the brain while you're taking amitriptyline, you’re more at risk of getting a side effect called 'serotonin syndrome', with symptoms such as agitation, tremor, shivering, increased heart rate and diarrhoea. Other medicines that increase serotonin activity include the following:
dapoxetine
duloxetine
fentanyl
illegal drugs such as cocaine, amphetamine (speed) and ecstasy (MDMA)
linezolid
lithium
methadone
rasagiline, selegiline of safinamide for Parkinson's
SSRI, tricyclic or related antidepressants, for example paroxetine, citalopram, amitriptyline, duloxetine, venlafaxine
triptans for migraine, such as sumatriptan
tryptophan.
Amitriptyline may alter the anti-blood-clotting effect of anticoagulant medicines such as warfarin. Your blood clotting time (INR) should be regularly monitored if you're taking these two medicines together.
If you get a dry mouth while you're taking amitriptyline you may find that tablets that are designed to dissolve and be absorbed from under the tongue, for example sublingual glyceryl trinitrate (GTN) tablets for angina, become less effective. This is because the tablets do not dissolve properly in a dry mouth. To resolve this, drink a mouthful of water before taking sublingual tablets.
The following medicines may increase the blood level of amitriptyline and could increase the risk of its side effects:
bupropion
cimetidine
methylphenidate
protease inhibitors for HIV such as ritonavir
SSRI antidepressants such as fluvoxamine, paroxetine and fluoxetine
terbinafine.
The following medicines may decrease the level of amitriptyline in the blood, so you might need a higher dose than normal dose if you're taking one of these:
barbiturates such as phenobarbital
carbamazepine
phenytoin
rifampicin.
Read more detailed information about medicines may interact with amitriptyline here
Last updated: 08.10.2019
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